Focal oiling for a piston assembly

ABSTRACT

A saddle portion for use with a piston head for use in an internal combustion engine is provided, that includes a saddle portion including an upper surface and a lower surface. At least two passages extend from the lower surface to the upper surface, and form a fluid path that permits cooling of the piston head.

TECHNICAL FIELD

The present disclosure relates to a piston head for an internal combustion engine, and in particular to a piston head that includes a fluid path located within the interior of the piston head.

BACKGROUND

In an effort to reduce the operating temperature of combusting gas in an internal combustion engine, fluid, such as oil or coolant, may be directed to the interior of a piston head. Fluid is delivered from a connecting rod passage that is located in the interior of a connecting rod, to a passage in a piston pin. The fluid is then delivered through an opening located in the saddle portion of the piston head to the interior of the piston head, where the fluid may be splashed against the interior of the piston head by the reciprocating motion of the piston.

One known method of delivering fluid to the piston head includes a hollow dowel pin for allowing fluid to pass through from a piston pin passage to the interior of the piston head crown. The hollow dowel pin connects the piston pin, an insert bearing and a saddle portion of the piston head. Oil is delivered from the hollow dowel pin to the interior of the piston head through a passage in the saddle portion of the piston head. The saddle passage is inserted at the center axis of the piston head, and fluid is generally directed towards the center of the interior surface of the piston head.

Another known method of delivering fluid to the piston head includes a retention pin to block the flow of fluid and an oil supply hole inserted along the center axis of the piston head as defined by the generally cylindrical circumference of the piston head. The retention pin is spaced laterally adjacent to the oil supply hole, and connects a wrist pin and an upper bearing shell to the saddle portion. The retention pin blocks any flow of fluid to the saddle portion of the piston head. The oil supply hole extends through a saddle portion of the piston head and communicates with an oil cooling space located in the piston head. The oil supply hole directs fluid into a central open region of the piston head.

However, as may be appreciated, the fluid may only be directed to the center of the interior surface of the piston head. There exists a need to direct the fluid towards any location on the interior of the piston head, depending on which specific areas may require additional cooling.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the piston head will become apparent to those skilled in the art from the following detailed description of embodiments thereof, when read in light of the accompanying drawings, in which:

FIG. 1 is an enlarged, partially exploded view of one embodiment of a piston and connecting rod assembly, including a piston head, a piston skirt, a piston pin, a pair of connecting bolts, a three piece slipper bearing assembly and a dowel;

FIG. 1A is an enlarged perspective view of Region 1A in FIG. 1;

FIG. 1B is an alternative illustration of FIG. 1;

FIG. 2 is a partial cross section of a portion of the piston head, piston pin and dowel during engine combustion;

FIG. 2A is an enlarged view of Region 1A in FIG. 1;

FIG. 2B is an alternative illustration of FIG. 2;

FIG. 3 is a partially cross section taken along lines 3-3 in FIG. 2;

FIG. 4 is an enlarged, exploded perspective view of the piston head and the dowel; and

FIG. 5 is an enlarged, exploded perspective view of the three piece slipper bearing assembly.

DETAILED DESCRIPTION

Exemplary illustrations are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual illustration, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints that will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

Turning now to the drawings and in particular to FIG. 1, an exemplar cross-head piston and connecting rod assembly 10 for an internal combustion engine is disclosed. In the illustration of FIG. 1, a connecting rod 12 may be coupled to a piston pin 14 by a pair of connecting bolts 16. A three piece slipper bearing assembly 18 may be coupled to the connecting rod 12, the piston pin 14 and a piston skirt 22. The piston skirt 22 may be part of a piston assembly 20, which includes a piston head 24.

The piston head 24 includes a crown portion 26 and a saddle portion 28. The saddle portion 28 may be connected to the crown portion 26 by a plurality of radially extending ribs 38. Although FIG. 1 illustrates a plurality of extending ribs 38, it is understood that any number of ribs, including a single extending rib may be utilized. Alternatively, another mechanism may be used.

The piston head also includes a piston pin connecting section 29, which includes a pair of opposing ears 40. The opposing ears 40 include a pair of piston ear openings 52, for receiving the piston pin 14 and the slipper bearing assembly 18. The piston skirt 22 includes a generally cylindrical wall 44 and a pair of oppositely disposed bosses 46. The bosses 46 include piston skirt openings 48 for receiving the piston pin 14 and the slipper bearing assembly 18. The piston head 24 and the skirt member are retained together by the piston pin 14. More specifically, the piston pin 14 may be received by both of the piston ear openings 52 and the piston skirt openings 48.

A lower surface 60 of the piston pin 14 may be coupled to the connecting rod 12 by the connecting bolts 16, which extend through two bolt openings 62 in the connecting rod 12, and into the piston pin 14 by two openings (not shown) disposed within the piston pin 14. As best seen by FIG. 2, a piston pin passage 64 extends from the lower surface 60 to an upper surface 54 and may be in fluid communication with a connecting rod opening 50 that receives fluid from a connecting rod passage (not shown). The connecting rod passage may be located within the interior of the connecting rod 12, and receives fluid, such as, but not limited to, oil or coolant that may be used for cooling the piston head during engine combustion.

A retaining pin or a dowel 30 may be disposed, at least in part, within the piston pin passage 64 and a slipper bearing retaining hole 66. The piston pin passage 64 and the slipper bearing retaining hole 66 are generally aligned with each other. The dowel 30 reduces relative movement between an upper slipper bearing 36 and the saddle portion 28 of the piston head 24. As best seen in FIG. 1A, the dowel 30 may include at least one sectioned portion 42 (shown in phantom line), that forms a passageway when the dowel 30 inserted into the piston and connecting rod assembly 10.

The sectioned portion 42 allows flow of a fluid received from the piston pin passage 64 to be directed to the piston head 24, and in particular to saddle portion 28, which will be discussed in greater detail below. It should be noted that while FIG. 1A illustrates the dowel 30 with one sectioned portion 42, it is understood that more than one sectioned portion 42 may be used as well. Moreover, it is also understood that although FIG. 1A illustrates sectioned portion 42 as a lateral section, sectioned portion 42 may include other equivalent configurations that may allow for fluid to pass through, such as, but not limited to, a pair of holes located in the dowel 30, as best seen in FIG. 1B.

FIG. 2 illustrates a partially cross sectioned view of the piston head 24, the dowel 30, the piston pin 14, and the slipper bearing assembly 18. The saddle portion 28 of the piston head 24 includes an upper surface 68 and a lower surface 80. A pair of passages 82 extends from the lower surface 80 to the upper surface 68, and form a fluid path 84 that permits cooling of the piston head 24. It should be noted that while FIG. 2 illustrates two passages 82, the saddle portion 28 may include only one passage, or, alternatively, more than two passages. At least one of the passages 82 may be offset at a predetermined distance D from a center axis A that extends along the piston head 24.

The crown portion 26 includes at least one cooling passage 90 in fluid communication with the passages 82. The cooling passage 90 may be formed by the extending ribs 38, and may be an open region, surrounded by the extending ribs 38. The fluid path 84 may be further formed by the cooling passage 90. The cooling passage 90 facilitates the flow of the fluid path 84 to a desired, predetermined location 92 within the interior of the piston head 24 that represents an area of elevated temperature during engine combustion.

The location of the predetermined location 92 may he dependent upon the area of an interior surface 94 of the crown portion 26 which, based upon the type of piston head 24, engine type, crown geometry or other factors, may need cooling. It should be noted that while FIG. 2 illustrates the predetermined location 92 disposed along the center axis A of the interior surface 94 of the crown portion 26, it will be appreciated that predetermined location 92 may be disposed at other locations along the interior surface 94. Moreover, although FIG. 2 illustrates one predetermined location 92, it is understood that more than one predetermined location 92 may also exist, as seen in FIG. 2B.

As best seen in FIG. 2A, both of the passages 82 may be equally offset at the distance D from the center axis A extending along the piston head. The distance D that the passages 82 are offset depends, at least in part, upon the predetermined location 92. For example, as best seen in FIG. 2, offsetting the passages 82 at the distance D from the center axis A allows for the fluid path 84 to contact the predetermined location 92. While an equal offset is illustrated, the offset may be different for each of the passages depending on the level of focused cooling required and the location of the focused cooling.

The passages 82 may also be angled with respect to the center axis A. An angle AN may be measured radially downward from the center axis A, and may be dependent upon the predetermined location 92. More specifically, the angle AN may vary from approximately one (1) degree to approximately twenty (20) degrees for each of the passages 82, and the dimension of the angle AN for each passage will determine, at least in part, the direction of the fluid path 84 within the interior of the crown portion 26. Thus, the angle AN may enhance cooling to the interior surface 94 of the crown portion 26 by maximizing the fluid flow to the predetermined location 92.

The offset at the distance D from the center axis A of the passages 82, as well as the variable angling of the passages 82 will allow for more precise directing of the fluid path 84 to the predetermined location 92 when compared to a conventional saddle passage inserted at the center axis A of the piston head 24. In the exemplary illustration shown in FIGS. 2 and 2A, the passages 82 are angled. However, it is understood that the passages 82 may not be angled.

In one illustrative approach, as seen in FIG. 2B, the passages 82 are parallel with the center axis A of the piston head 24. The purpose of orienting the passages 82 generally parallel with the center axis A may be to guide or direct the fluid path 84 towards the predetermined location 92. For example, orienting the passages 82 to be parallel with the center axis A may direct the fluid path 84 in a generally upward direction, towards more than one desired, predetermined location, as best seen by FIG. 2B.

As best seen in FIG. 2A, the lower surface 80 includes a channel 86 that may allow for one of the passages 82 to be in fluid communication with the other one of the passages 82. The lower surface 80 may also include at least one dowel aperture 88 that may be interposed within at least a portion of the channel 86. The dowel aperture 88 selectively receives the dowel 30. The sectioned portion 42 of the dowel 30 further forms the fluid path 84. More specifically, the sectioned portion 42 creates a passageway between the dowel 30 and the saddle portion 28 that allows for fluid communication with the channel 86. That is, the sectioned portion 42 represents an empty volume of space when the dowel 30 may be assembled to the saddle portion 28. The empty volume of space that may be created by the sectioned portion 42 will allow for the fluid path 84 to pass through, and thereby allowing for fluid communication within the channel 86.

FIG. 3 illustrates a partially cross sectioned view of the piston head 24, and in particular the crown portion 26. The crown portion 26 includes the extending ribs 38 and the cooling passage 90. In the illustrative approach shown in FIGS. 2, 2A, 2B, and 3, the extending ribs 38 are circumferentially spaced apart such that the cooling passage 90 may be aligned with the center axis A. However, it is understood that the extending ribs 38 may be oriented such that the cooling passage 90 may be located at a predetermined distance offset from the center axis A, Moreover, although FIG. 3 illustrates the extending ribs 38 forming one predetermined location 92, it is understood that the extending ribs 38 may form more than one predetermined location 92.

FIG. 4 illustrates the lower surface 80 of the saddle portion 28. The lower surface 80 includes the channel 86 that extends along a portion of the lower surface 80, forming the fluid path 84. The channel 86 may extend radially outwardly from the center axis A of the piston head 24. The channel 86 provides a cushion of fluid between the lower surface 80 and the upper slipper bearing 36 of slipper bearing assembly 18. The cushion of fluid may assist in reducing noise and wear that may be created when the upper surface 54 of the upper slipper bearing 36 contacts the lower surface 80 during engine combustion.

As discussed above, the saddle portion 28 may include only one passage 82, and may be in fluid communication with the channel 86. Alternatively, the saddle portion 28 may include two or more passages 82. The channel 86 allows for at least one of the passages 82 to be in fluid communication with at least one other passage 82. The passages 82 may be oriented such that one of the passages 82 may be located on one end of the channel 86, and the other of the passages 82 may be located on the opposing end of the channel 86. Both of the passages 82 may be equally offset or offset at different predetermined distances D from the center axis A of the piston head 24.

The dowel aperture 88 may be interposed at the center axis A of the piston head 24. Moreover, the dowel aperture 88 may also be interposed between the passages 82 such that the dowel aperture 88 may be equally offset from the passages 82 by the distance D.

FIG. 5 illustrates the three piece slipper bearing assembly 18 that includes the upper slipper bearing 36, and a pair of lower slipper bearing half shells 98. The slipper bearing retaining hole 66 may be disposed on the upper slipper bearing 36, and receives the dowel 30. The upper slipper bearing insert 36 and the lower slipper bearing half shells 98 may be configured to be received by the piston ear openings 52. The slipper bearing assembly 18 may be configured to fit together by a pair of opposing notches 100 that are disposed on both ends of the upper slipper bearing 36. The notches 100 receive the lower slipper bearing half shells 98.

The present invention has been particularly shown and described with reference to the foregoing embodiments, which are merely illustrative of the best modes for carrying out the invention. It should be understood by those skilled in the art that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention without departing from the spirit and scope of the invention as defined in the following claims. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the invention should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application. 

1. A saddle portion for use with a piston head for use in an internal combustion engine, comprising: an upper surface and a lower surface; and at least two passages that extend from said lower surface to said upper surface; wherein said passages form a fluid path that permits cooling of the piston head.
 2. The saddle portion of claim 1, wherein at least one of said passages is offset at a predetermined distance from a center axis of the piston head.
 3. The saddle portion of claim 1, wherein each of said passages are generally equally offset from a center axis of the piston head.
 4. The saddle portion of claim 1, wherein said passages are angled with respect to a center axis of the piston head.
 5. The saddle portion of claim 4, wherein said passages are radially outwardly angled between approximately one degree to approximately twenty degrees.
 6. The saddle portion of claim 1, wherein said passages are generally parallel with a center axis of the piston head.
 7. The saddle portion of claim 1, said lower surface including a channel for allowing one of said passages to be in fluid communication with another one of said passages.
 8. The saddle portion of claim 7, wherein said lower surface further includes at least one dowel aperture interposed within at least a portion of said channel.
 9. The saddle portion of claim 8, said dowel aperture selectively receiving a dowel, and wherein said dowel includes at least one dowel passageway that allows for fluid communication with said channel.
 10. The saddle portion of claim 1, wherein an outlet of said passages is selectively aligned in fluid communication with a corresponding cooling passage within the piston head.
 11. The saddle portion of claim 10, wherein said outlet is selectively positioned to facilitate increased cooling flow in a desired region of the piston head.
 12. A saddle for use with a piston head for use in an internal combustion engine, comprising: a lower surface; and said lower surface including a channel; wherein said channel extends along a portion of said lower surface to form a fluid path.
 13. The saddle portion of claim 12, wherein said channel extends radially outwardly from a center axis of said piston head.
 14. The saddle portion of claim 12, further including an upper surface of said saddle portion and at least one passage extending from said upper surface to said lower surface and in fluid communication with said channel.
 15. The saddle portion of claim 14, wherein an outlet of said passages is selectively aligned in fluid communication with a corresponding cooling passage within the piston head.
 16. The saddle portion of claim 15, wherein said outlet is selectively positioned to facilitate increased cooling flow in a desired region of the piston head.
 17. The piston head of claim 14, wherein said piston head further includes a crown portion connected to said saddle portion, and said crown portion including at least one cooling passage in fluid communication with at least one of said passages, and said cooling passage facilitates the flow of said fluid path to at least one desired, predetermined location within the interior of said piston head.
 18. The saddle portion of claim 14, further including a second passage extending from said upper surface to said lower surface, wherein said channel allows for said at least one passage to be in fluid communication with said second passage.
 19. The saddle portion of claim 18, wherein at least one of said at least one passage and said second passage are offset at a predetermined distance from the center axis of the piston head.
 20. The saddle portion of claim 12, wherein said lower surface further includes at least one dowel aperture interposed within at least a portion of said channel.
 21. The saddle portion of claim 20, said dowel aperture selectively receiving a dowel, and wherein said dowel includes at least one dowel passageway that allows for fluid communication with said channel.
 22. A piston head for use in an internal combustion engine, comprising: a crown portion including at least one cooling passage for forming a fluid path that permits cooling of the piston head; a saddle portion connected to said crown portion, said saddle portion including an upper surface and a lower surface; at least two passages extending from said lower surface to said upper surface and in fluid communication with said at least one cooling passage; and a channel formed in said lower surface and extending radially outwardly to allow for one of said passages to be in fluid communication with the other one of said passages; wherein said at least one cooling passages facilitates the flow of said fluid path to at least one desired, predetermined location within the interior of the piston head that represents an area of elevated temperature during engine combustion.
 23. The piston head of claim 22, wherein at least one of said passages is offset at a predetermined distance from a center axis of the piston head.
 24. The piston head of claim 22, wherein said lower surface further includes at least one dowel aperture interposed within at least a portion of said channel, said dowel aperture selectively receiving a dowel and including at least one dowel passageway that allows for fluid communication with said channel.
 25. A method of forming a fluid path in a saddle portion of a piston head, comprising the steps of: creating a channel along a portion of a lower surface of said saddle portion of the piston head; and providing a plurality of passages located within said saddle portion and in fluid communication with said channel, offsetting said passages from a center axis of said piston head.
 26. The method of claim 25, further comprising the step of angling said passages no more than approximately twenty degrees with respect to the center axis.
 27. The method of claim 26, further comprising the step of arranging an outlet of each of said passages to maximize fluid delivery to a preselected region within the piston head to maximize cooling. 